【面试题】从链表尾部算起，删除第n个节点

type ListNode struct {
    Val  int
    Next *ListNode
}

func removeNthFromEnd(head *ListNode, n int) *ListNode {
    if head != nil {
        // 获取长度
        var hLen int
        for l := head; l != nil; l = l.Next {
            hLen++
        }
        // 计算删除位置
        n = hLen - n + 1
        front := head
        now := head.Next
        for i := 2; i < n && now.Next != nil; i++ {
            front = now
            now = front.Next
        }
        front.Next = now.Next
        now = nil
        return head
    }
    return nil
}

应该考虑只用一次循环来实现

用一个指针p保留当前节点i的前面n节点

每次迭代，p，i都叠加

当i是末尾时，删除p

单链表

func removeNthFromEnd(head *NodeList, n int) *NodeList {

    if head == nil{
        return nil
    }

    if n < 0 {
        return head
    }

    i, j := head, head  
    z := 0

    for ; i.Next != nil; i=i.Next{
        if z < n+ 1 {
            z++
            continue
        }
        j = j.Next
    }

    if(z > n){
        j.Next = j.Next.Next
    }

    return head;
}

正解